// with traceAdvanceSema held.
//
// No more than one goroutine may be in traceReadCPU for the same
// profBuf at a time.
//
// Must not run on the system stack because profBuf.read performs race
// operations.
func traceReadCPU(gen uintptr) bool {
	var pcBuf [traceStackSize]uintptr

	data, tags, eof := trace.cpuLogRead[gen%2].read(profBufNonBlocking)

		statusWriter = statusWriter.writeGoStatus(ug.goid, ug.mid, status, ug.inMarkAssist, ug.stackID)
	}
	statusWriter.flush().end()

	// Read everything out of the last gen's CPU profile buffer.
	traceReadCPU(gen)

	// Flush CPU samples, stacks, and strings for the last generation. This is safe,
	// because we're now certain no M is writing to the last generation.
	//